1. Field of the Invention
The present invention relates to an exhaust system, and more particularly to an exhaust system for a motorcycle capable of reducing the weight of the exhaust system without sacrificing a cushioning characteristic of a seat and a range of vertical movement of a rear wheel.
2. Description of the Background Art
Exhaust systems for motorcycles in which a pair of left and right mufflers are disposed on a rear portion of a vehicular body have been available in the background art. For example, Japanese Patent Laid-open No. Hei 5-77776 entitled xe2x80x9cLuggage Box for Motorcyclexe2x80x9d and Japanese Patent Laid-open No. Sho 59-49313 entitled xe2x80x9cExhaust System for Motorcyclexe2x80x9d describe exemplary exhaust systems of the background art.
Referring to FIGS. 1 and 4 of the 5-77776 (""776) document, a motorcycle in which exhaust pipes 14 and 15 extend rearwardly from an engine 11 and are connected to a collecting chamber 16 is shown. Two exhaust pipes 17 extend upwardly from left and right portions of the collecting chamber 16, and left and right exhaust mufflers 18 are connected to these exhaust pipes 17.
Referring to FIGS. 1 and 2 of the 59-49313 (""313) document, a motorcycle in which an exhaust pipe 14 extends rearwardly from a front cylinder 7a of an engine 7 is shown. A muffler 15 is connected to the exhaust pipe 14, an exhaust pipe 16 extends rearwardly from a rear cylinder 7b of the engine 7 and a muffler 17 is connected to the exhaust pipe 16 via an extension pipe 18. A front portion of the muffler 15 is in communication with a front portion of the muffler 17 by means of a communication pipe 23.
The present inventor has determined that the systems of the background art suffer from the following problems. If the exhaust pipes 17 described in the ""776 document are in communication with each other at positions immediately before the exhaust mufflers 18 by using a communication pipe, e.g., the communication pipe 23 described in the ""336 document, then the exhaust pipes 17 can be collected into one pipe and the weight of the exhaust system can be reduced. However, to dispose the communication pipe under a seat 9 at a position immediately before the exhaust pipes 18, it is required to reduce the thickness of a cushioning material of the seat 9. Accordingly, a cushioning characteristic of the seat 9 is degraded and riding comfort is sacrificed.
It also may be possible to lower the position of the communication pipe along with the positions of the exhaust pipes 17 and the exhaust mufflers 18 to cope with this inconvenience, e.g., to eliminate the need for thinning the cushion material of the seat 9. However, a vertical movement of a rear wheel 7 must be reduced in order to prevent interference of the rear wheel 7 with the exhaust pipes 17, the exhaust mufflers 18, and the communication pipe. As a result, the integrity and operability of the rear suspension is sacrificed.
The present invention overcomes the shortcomings associated with the background art and achieves other advantages not realized by the background art.
An object of the present invention is to provide an improved exhaust system structure.
An object of the present invention is to provide a motorcycle exhaust system having a reduced weight without sacrificing a cushioning characteristic of a seat and a range of vertical movement of a rear wheel.
One or more of these and other objects are accomplished by an exhaust system for a motorcycle having a tandem seat, the exhaust system comprising an exhaust pipe extending rearwardly from an engine of the motorcycle; a pair of first and second mufflers connecting with a rear end of the exhaust pipe; a first branch pipe and a second branch pipe forming the rear end of the exhaust pipe; and a recess formed beneath a driver""s seat and a passenger""s seat in the tandem seat; wherein the first branch pipe is connected to the first muffler and the second branch pipe is connected to the second muffler.
One or more of these and other objects are accomplished by the combination of a motorcycle having an engine, a longitudinal centerline, a rear wheel, a rear cowl, a tandem seat, and a body frame and an exhaust system, the exhaust system comprising an exhaust pipe extending rearwardly from an engine of the motorcycle; a pair of left and right mufflers connecting with a rear end of the exhaust pipe; a first branch pipe and a second branch pipe forming the rear end of the exhaust pipe; and a recess formed beneath a driver""s seat and a passenger""s seat in the tandem seat; wherein the first branch pipe is connected to the left muffler and the second branch pipe is connected to the right muffler through the recess.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.